What environmental factor is most closely linked to mold development?

Increased humidity is the environmental factor most closely linked to mold development because mold thrives in moist environments. Mold spores are naturally present in the air, and when they land on surfaces that are damp, they begin to colonize and grow. Humidity levels above 60% create an optimal environment for mold spores to germinate and flourish, especially in areas that are prone to moisture, such as bathrooms, kitchens, and basements.

High levels of dust can certainly contribute to mold growth in an indirect way, as dust can provide a food source for mold. However, without adequate moisture, dust alone would not lead to mold development. Low air circulation can also contribute to mold problems by allowing moisture to linger in local areas, but it is humidity that directly influences mold growth potential. Excessive light from windows doesn’t have a significant effect on mold growth; in fact, some light can deter mold when it helps dry out damp areas. Therefore, increased humidity is the primary environmental factor that supports mold development.